[Internet Archive] handle IA specific headers

Making this more specific to IA:

Support x-amz-* and x-archive-* headers

Specify standard x-archive-meta-* headers

Handle multiple headers, e.g.:
* x-archive-meta01-collection:foo
* x-archive-meta01-collection:bar

Additional attributes for files, specific to IA headers:
* :auto_make_bucket
* :cascade_delete
* :ignore_preexisting_bucket
* :interactive_priority
* :keep_old_version
* :queue_derive
* :size_hint